Field of the Invention
The present invention relates to a power supply apparatus configured to control a DC voltage to be output based on information fed back from an output DC voltage, and an image forming apparatus including the power supply apparatus.
Description of the Related Art
There have hitherto been an AC/DC converter configured to receive an AC voltage and output a DC voltage and a DC/DC converter configured to receive a DC voltage and output a DC voltage different from the input DC voltage. In such AC/DC converter and DC/DC converter, a DC voltage to be output varies among converters due to a variation in component configured to determine an output DC voltage. Therefore, for example, in order to reduce a difference among converters in DC voltage to be output, a DC voltage to be output is appropriately adjusted. For example, in Japanese Patent No. 5826158, there is disclosed a technology of adjusting a DC voltage to be output by inputting a signal to a feedback voltage.
A processor configured to output a PWM signal for adjusting a DC voltage to be output generates a PWM signal, for example, through use of a timer function based on a reference clock. Further, some processors set the frequency of a reference clock of the processor at the time of a power saving mode to be lower than that at the time of a normal mode. When the PWM signal at the time of the power saving mode has the same duty resolution as that at the time of the normal mode, because the frequency of the PWM signal at the time of the power saving mode is lower than that at the time of the normal mode, a ripple of a DC voltage to be output increases. Further, when the PWM signal at the time of the power saving mode has the same frequency as that at the time of the normal mode, the duty resolution of the PWM signal decreases, and there is a risk in that the DC voltage to be output may not be satisfactorily adjusted.